A trust has rejected an offer to become a full member of a neighbouring hospital group amid concerns about “cherry picking”, stability and the loss of clinical services.

North Middlesex University Hospital Trust’s board decided last week not to join the Royal Free London group, a move that has been mooted since September 2017.

A report said NMUH had spoken to local politicians, commissioners, regulators and local authorities and “the very clear message we heard was that they could see little benefit and significant risk for [the trust] and its local populations in joining the ‘Group’ structure.”

It added: “We have not found, heard or seen any evidence which, taken together, could be interpreted as a robust case for North Mid to seek to enter into a closer partnership with Royal Free London group, ie by becoming a full member of the RFL group, nor which makes a strong case for such a partnership being necessary to address the five top challenges that North Mid has previously articulated as being essential for it to address.

“On the contrary, we have received a significant weight of evidence that becoming a full member of the RFL group could risk the stability, local accountability and highly valued services particular to our local communities, and that the advantages of RFL membership would be substantially dwarfed by the disadvantages it would have on North Mid and its local populations.”

The trust will continue to be a “clinical partner” of the Royal Free Group.

West Hertfordshire Hospitals Trust has been in a “buddying” arrangement with Royal Free since 2016 and its chief executive from then until earlier this year had been the Hampstead trust’s former director of service transformation.

The organisations said clinical staff had been working on best practice on pneumonia, urgent gall bladder problems, prostate conditions, and other conditions.

A paper presented to the North Middlesex board noted some improvement in one of the pathways which it had worked on with the Royal Free in a “clinical practice group”.

But it added: “In summary, it was clear the medical leads felt strongly that North Mid’s clinical partnership with the Royal Free London group is valuable and should continue, but that there would be greater benefit for North Mid in working with other organisations in the local area than pursuing a closer relationship with Royal Free London group.”

NMUH’s chief executive Maria Kane said in a statement: “Although full membership is no longer on the table, I am delighted that the North Mid board today reiterated its continued commitment to a strong and productive clinical partnership with the Royal Free London group.

“We know, of course, that North Mid cannot ‘sit still’ and must continue to tackle the challenges it faces. So, alongside our continued clinical partnership with RFL group, we will look to develop stronger relationships and joined up working with a range of local partners, both on a population health basis, and case by case with local organisations to share efficiencies and mutually improve.”

She added: “I would like to put on record, on behalf of the trust, that we are very grateful for the significant support the Royal Free has given to North Mid over the past couple of years.”

In a statement, a spokesman for the Royal Free said: “North Middlesex University Hospitals Trust joined the Royal Free London group as a clinical partner in September 2017 with a view to potentially joining as a full member at a later date. NMUH have decided that exploring the possibility of becoming a full member – something which would require RFL board approval and be seen as a ‘significant transaction’ – is not the right option for them at this time.”